TITLE: GCN CIRCULAR NUMBER: 10952 SUBJECT: GRB100713A: Swift X-ray afterglow detection DATE: 10/07/13 16:46:58 GMT FROM: Neil Gehrels at GSFC V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU), E. A. Hoversten (PSU), K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team: Swift began a target of opportunity observation of GRB100713A on July 13, 2010 at 16:30 UT, approximately 1.9 hours after the burst was detected by INTEGRAL. Swift data for these observations utilize Target ID 20143. The XRT began observing the field at 16:20:34.3 UT, 6.2 ks after the INTEGRAL trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 255.20192, 28.39489 which is equivalent to: RA(J2000) = 17h 00m 48.46s Dec(J2000) = +28d 23' 41.6" with an uncertainty of 4.9 arcseconds (radius, 90% containment). This location is 29 arcseconds from the INTEGRAL position, within the INTEGRAL error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (5.01e+20 cm^-2, Kalberla et al. 2005), with an excess column of 7.2 (+8.61/-6.14) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 6246 seconds after the INTEGRAL trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.06. Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)